The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
This section provides background information related to the present disclosure which is not necessarily prior art.
Groundwater and waste streams can be contaminated with contaminants such as volatile organic compounds (VOCs), or dissolved gases, such as Radon, CO2, CH4, H2S, etc.) which require removal in order to reuse or discharge the water. For the purpose of the following discussion, it will be understood that reference to the term “VOCs” includes any combination of VOCs and/or the above mentioned dissolved gasses. Air strippers which direct streams of air into a flowing stream of the contaminated water are used to transfer the VOCs from the water (aqueous phase) to the air stream (gaseous phase), which permits removal of the VOCs. Known air strippers include tower designs and stacked tray designs.
Chemical changes during the air to water contact often results in mineral deposits, biologic fouling, and other precipitant deposits occurring at internal process unit surfaces. Cleaning known air stripper designs is cumbersome and time consuming due to the necessary disassembly required and the size/weight of the components that must be removed to access the fouled components.
Present day tray air strippers make use of a plurality of horizontally arranged trays stacked in spaced apart relationship one on top of the other. One example of a present day air stripper apparatus is disclosed in U.S. Pat. No. 8,523,152 to Spicer, issued Sep. 3, 2013, assigned to the assignee of the present application, the entire disclosure of which is hereby incorporated by reference into the present application. Each tray includes a downcomer portion through which a fluid flows from the tray positioned immediately above it. Downcomers also effect air sealing to prevent high volumes of air from passing up through the water drain channel formed by the downcomer.
Forming each tray with its own downcomer attached thereto, while highly effective for the removal of volatile organic compounds from the fluid, nevertheless creates a more complex tray design. The use of additional gaskets is also required to ensure that the proper sealing occurs around the upper end of the downcomer when the tray is slidably inserted into a housing of the air stripper. The presence of the downcomer as a permanent portion of the tray also increases the cost of manufacture of the tray and, in some instances, may necessitate additional care and effort in cleaning and handling the tray during cleaning, as well as additional space in storing spare trays.